On the 60 minute, TZA is in an orderly down channel, with the 20 EMA under the 50 EMA. STO is in the over bought territory. Not pressed with much urgency in this time frame. But look at the daily next.
On the daily chart, TZA looks a lot more bullish. Recent double bottom with tremendous positive divergence. And now we have a nice looking cup with handle with favorable volumes. Instead of playing VXX, TZA seems a better instrument, in my opinion. I would allocate more on TZA over the volatility plays (VXX, TVIX).